On Tue, Feb 2, 2016 at 10:06 AM, Snyder, Emile <emsnyder@xxxxxxxx> wrote: > Hi all, > > I was wondering if anyone had any insights as to the status of http://tracker.ceph.com/projects/ceph/wiki/Zero-copy_bufferlists? Poking around in the buffer code I see that there is some code there to handle zero copy with buffer::raw, but that it's disabled (the if (false && read_fd_zero_copy(fd, len) == 0) in buffer::list::read_fd), and that the read path for osd's using FileStore doesn't appear to go through buffer anyway (FileStore::read uses safe_pread) > > > > Was this direction determined to not be worth it, or is it just that no one has had the time to keep pursuing it? I didn't do any of this work, but I think there ended up being (a) not enough time available, and (b) some issue with using pipes as described there — the overhead was too high for the typical amount of memory we use in a buffer, maybe? Or we were just trying to allocate too many pipes for the kernel to handle well, or for us to handle, or something. -Greg -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
